Colorimetric method for estimation of carbaryl and its residues on grains.

A new colorimetric method for the estimation of carbaryl, 1-naphthyl N-methylcarbamate, based on its reaction with diazotized o-toluidine, has been described. The absorption max. of the red colour formed is measured at 520 nm. The method is sensitive to 0.1 mug carbaryl/20 g sample, with an estimation limit of 1 mug, and can be applied to 10% dust formulations of carbaryl. It is applicable to rice, jowar, wheat and groundnut pods.